Synthesis, structure and applications of amorphous diamond

Abstract

The relation was investigated between the compressive stress, the substrate temperature and the microstructure of amorphous carbon films deposited from the plasma stream of a cathodic vacuum arc with a curved magnetic filter. A pressure-temperature phase diagram is presented in which the results of a number of depositions at various substrate bias levels and temperatures are plotted. The microstructure of each film was determined by electron energy loss spectroscopy and electron diffraction. The diagram shows clear regions in which sp 2 and sp 3 material is formed, together with a transitional region of material of mixed character, along the Berman-Simon phase boundary between diamond and graphite. The structure of tetrahedral amorphous networks, of which the sp 3 bonded material is an example, was studied using an approach based on the properties of common structural fragments. Important features of the radial distribution function could be understood in this way. The effect of compressive stress on refractive index is also discussed.